Data carrier which can be operated without contact

ABSTRACT

The invention relates to a data carrier ( 1 ) having an integrated circuit ( 7 ) and at least one insulating supporting substrate ( 10 ) on which a transfer element ( 2 ) for transferring data to an external device is disposed. The integrated circuit ( 7 ) can alternatively be mounted in the data carrier ( 1 ) directly or packed in an electronic module ( 4 ). For establishing an electric connection between the integrated circuit ( 7 ) or electronic module ( 4 ) and the transfer element ( 2 ), the data carrier ( 1 ) has electroconductive surfaces ( 3, 17 ) opposite the two main faces of the electronic module ( 4 ) or integrated circuit ( 7 ). The electroconductive surfaces ( 3, 17 ) are connected with the opposing contact surfaces ( 5 ) of the electronic module ( 4 ) or the contacts ( 8 ) of the integrated circuit ( 7 ) and connected in pairs with the electroconductive surfaces ( 3, 17 ) disposed on the other side of the electronic module ( 4 ) or integrated circuit ( 7 ). Each pair of electroconductive surfaces ( 3, 17 ) is further electrically connected with the transfer element ( 2 ). The transfer element ( 2 ) can be formed as a printed coil, the coil ends ( 3 ) being widened and each forming one of the electroconductive surfaces ( 3, 17 ) of each pair.

BACKGROUND OF THE INVENTION

This invention relates to a data carrier having an integrated circuitand at least one insulating supporting substrate on which a transferelement is disposed for transferring data to an external device, and toa method for producing such a data carrier.

A data carrier of the abovementioned kind is known from EP 0 756 244 A2whose disclosure is taken as a basis for the further description. EP 0756 244 A2 describes a circuit unit having an insulating supportingsubstrate on which a conductive flat coil is located. The coil canconsist of a plurality of coil layers separated by insulating layers. Inorder to interconnect the individual coil layers into a coil, each ofthe insulating layers has at least one hole. The coil ends can beconnected with an integrated circuit or an electronic module containingthe integrated circuit solely if the coil ends touch the terminals ofthe integrated circuit or the contacts of the module. The individualturns of the coil can be so disposed and dimensioned that the circuitunit is embossable without restriction within an area specified by thestandard.

It is especially important for perfect operation of the data carrierthat the electric connection between the transfer element, which can beformed for example as a coil, and the integrated circuit, which isoptionally mounted in the data carrier in the form of an electronicmodule, be reliable throughout the life of the data carrier.

It is therefore the problem of the invention to design the structure ofthe data carrier in such a way as to ensure a lastingly reliableelectric connection between the transfer element and the integratedcircuit or electronic module.

SUMMARY OF THE INVENTION

This problem is solved by the feature combinations of the independentclaims.

The essential aspect of the invention is that the data carrier is formedso as to permit double-sided contacting, i.e. contacting of both mainfaces of the integrated circuit or the electronic module containing theintegrated circuit, with the transfer element.

This manner of contacting has the advantage of eliminating the effort ofa soldering process or of metering conductive adhesive for contacting,while nevertheless achieving a very reliable and long-lived electricconnection between transfer element and electronic module or integratedcircuit. Whenever the contacts of the integrated circuit or electronicmodule come away from the transfer element on one side as a result ofbending stress or other effects, thereby worsening the electricconnection, the exactly opposite effect occurs on the other side of theintegrated circuit or electronic module so as to compensate the adverseeffects. The described motion causes the transfer element to be pressedagainst the contacts of the integrated circuit or electronic module onthe opposite side of the integrated circuit or electronic module, sothat the electric connection between integrated circuit or electronicmodule and transfer element is at least not clearly worsened or evenimproved. This ensures that the electronic data carrier still worksreliably even upon strong bending stress.

Furthermore, regardless of the cause for detachment of the transferelement from one or more contacts of the electronic module or integratedcircuit, the redundant design of the connecting points reduces the riskof a resulting disruption of service. The described compensation orredundancy effect presupposes, however, that the electronic module orintegrated circuit used has contacts which are accessible from both mainfaces, or two sets of contacts which are redundant relative to eachother, one set being disposed on each main face. This is already thecase in particular with so-called lead-frame modules wherein theintegrated circuit is disposed on a thin metal frame. The invention cantherefore be used especially advantageously in conjunction withlead-frame modules.

However, the invention also offers advantages with electronic modules orintegrated circuits which are only contactable via one of the two mainfaces. In this case one also gains an additional degree of freedom forproducing the data carrier since the transfer element is contactable indifferent mounting positions of the electronic module or integratedcircuit.

A further advantage of the invention is that, starting out from the datacarrier known from EP 0 756 244 A2, the above-described improvement ofthe electric connection between transfer element and integrated circuitor electronic module can be obtained by the relatively simple measure ofdouble-sided contacting, which can be realized without introducing a newtechnique into the production process and thus hardly increasesproduction costs.

The transfer element is preferably printed on insulating layers of thedata carrier in the form of a coil, the screen printing technique beingespecially well suited.

The invention will be explained below with reference to the drawings. Achip card is selected here as an embodiment for the data carrier, and aprinted coil for the transfer element. The data carrier can of coursealso be designed differently and be integrated for example into a key oranother object of daily use. For the transfer element one can also usean electrostatic coupling surface for example.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows an embodiment of the inventive chip card wherein theintegrated circuit is embedded in the card body in the form of anelectronic module, in a plan view,

FIG. 2 shows a further embodiment of the inventive chip card wherein theintegrated circuit is embedded in the card body directly, in a planview,

FIG. 3 shows a layer structure of the chip card shown in FIG. 1 beforelamination, in cross section along line A—A,

FIG. 4 shows the chip card shown in FIG. 1 in cross section along lineA—A,

FIG. 5 shows a layer structure of the chip card shown in FIG. 2 beforelamination, in cross section along line A—A, and

FIG. 6 shows the chip card shown in FIG. 2 in cross section along lineA—A.

DETAILED DESCRIPTION

FIG. 1 shows an embodiment of the inventive chip card wherein theintegrated circuit is packed in an electronic module, in a plan view.Chip card 1 is designed for noncontacting data exchange with an externaldevice and fulfills ISO standard 7810 with respect to its outerdimensions. Within an area limited by a wavy line one sees a view of theinner structure of chip card 1. For clarity's sake the individual cardlayers are not shown but rather only the components embedded in orbetween the layers. These components consist in particular of coil 2whose ends 3 are greatly widened in order to establish an optimalelectric contact with electronic module 4 in which integrated circuit 7is embedded. Integrated circuit 7 is covered by casting body 6 andelectrically connected with contact surfaces 5 of electronic module 4.Electronic module 4 is preferably formed as a lead-frame module whereinmetallic contact surfaces 5 serve as a supporting substrate forintegrated circuit 7 together with casting body 6. Contact surfaces 5are each electrically connected with widened ends 3 of coil 2 in eachcase. Further, the backs of contact surfaces 5 are connected withelectroconductive surfaces 17, which are not visible in FIG. 1 sincethey come to lie under coil ends 3. Each of electroconductive surfaces17 is in addition connected with one coil end 3.

Coil 2 including widened coil ends 3 as well as electroconductivesurfaces 17 are preferably produced by printing technology. One producesthe electric connection between coil ends 3 or electroconductivesurfaces 17 and contact surfaces 5 by connecting the individual layersconstituting chip card 1 and carrying coil 2 or electronic module 4 intoa card body by lamination, so that coil ends 3 or electroconductivesurfaces 17 and contact surfaces 5 now lastingly touch each other. Thiscontact between coil ends 3 or electroconductive surfaces 17 and contactsurfaces 5 can be established alternatively at a time when printed coilends 3 or electroconductive surfaces 17 are totally dried off or at atime when the drying process is not yet over. According to theinvention, contact surfaces 5 are connected with coil ends 3 on eachside. As explained above, this cannot be seen in FIG. 1 sinceelectroconductive surfaces 17, which are connected with the back ofcontact surfaces 5, come to lie exactly under coil ends 3 shown and aretherefore not visible. The inventive contacting technology is clearlyrecognizable in FIGS. 3 to 6, however, and will be described in detailwith reference to these figures.

FIG. 2 shows a further embodiment of inventive chip card 1 which differsfrom FIG. 1 only in that integrated circuit 7 is not packed inelectronic module 4 but embedded directly in the card body. On itssurface, integrated circuit 7 has contacts 8 which are in touchingconnection with coil ends 3. As in FIG. 1, coil ends 3 are additionallyconnected in the embodiment of FIG. 2 with electroconductive surfaces 17which are again connected with contacts 8 disposed on the back ofintegrated circuit 7.

FIG. 3 shows the layer structure of chip card 1 shown in FIG. 1 beforelamination of the individual layers, in cross section along line A—A. Inthe embodiment shown in FIG. 3 chip card 1 consists of six individuallayers. Electronic module 4 is disposed in layer 9 in such a way thatcontact surfaces 5 of electronic module 4 come to lie in a recess oflayer 9 and casting body 6 protrudes beyond layer 9. On each side oflayer 9 there are layers 10 and 11. Layer 10 carries printed coil 2including coil ends 3, whereby coil ends 3 come to lie opposite contactsurfaces 5 of electronic module 4. Layer 11 is disposed on the side oflayer 9 beyond which casting body 6 protrudes and contains recess 12 forreceiving casting body 6. Instead of recess 12, layer 11 can also have aperforation completely penetrating layer 11. Further, layer 11 carrieselectroconductive surfaces 17 which can be electrically connected withcoil ends 3 disposed on layer 10 via at least one plated-through hole 13in layer 9. Toward the outside of the card, layer 11 is followed byanother layer 14 and finally cover layer 15. Layer 10 is followed towardthe outside of the card by cover layer 16. The layer structure can varywithin wide limits depending on the area of use. In particular one candispense with cover layers 15 and 16 or layers 10 and 14. All layers canconsist of the materials customarily used in chip cards, for examplePVC, ABS, PETG, polycarbonate, etc.

FIG. 4 shows chip card 1 shown in FIG. 1 in cross section along lineA—A. Chip card 1 shown in FIG. 4 was produced by laminating the stack ofsingle layers shown in FIG. 3. Before the layers are stacked they areprovided with the components shown in FIG. 3, such as coil 2 togetherwith widened coil ends 3, electroconductive surfaces 17, plated-throughholes 13 and electronic module 4. FIG. 4 clearly shows the inventivedouble-sided contacting of contact surfaces 5 of electronic module 4through coil ends 3 and electroconductive surfaces 17. The electricconnection between coil ends 3 and contact surfaces 5 is established bythe laminating process. Coil ends 3 are thereby pressed against theupper side of contact surfaces 5, and electroconductive surfaces 17 areelectrically connected with coil ends 3 by at least one plated-throughhole 13 in each case and pressed against the lower side of contactsurfaces 5. This procedure achieves double-sided contacting of contactsurfaces 5 so that a reliable electric connection between coil 2 andintegrated circuit 8 is ensured even when coil ends 3 are detached fromcontact surfaces 5 for example as a result of bending stress on chipcard 1. In this case the electric contact is still maintained throughelectroconductive surfaces 17.

A further effect of double-sided contacting is that one can useelectronic modules 4 of different constructions for chip card 1 shown inFIG. 4, it being irrelevant whether contacting of electronic module 4 ispossible only from the upper side, only from the lower side or on bothsides. In case electronic modules 4 are only contactable on one side,one of course does not have the advantage of higher reliability of theelectric connection as with double-sided contacting. However, the cardstructure shown in FIG. 4 offers the advantage over conventional cardstructures with one-sided contacting that the card structure can be usedfor different electronic modules 4 in an unchanged form.

FIG. 5 shows the layer structure of chip card 1 shown in FIG. 2 beforelamination of the individual layers, in cross section along line A—A.The layer sequence corresponds to the layer sequence shown in FIG. 3 butlayers 9 and 11 are modified. According to FIG. 5 layer 9 has hole 18 inwhich integrated circuit 7 is embedded. Further, layer 9 has at leastone plated-through hole 13. In contrast to FIG. 3, layer 11 shown inFIG. 5 has no recess 12 and only carries electroconductive surfaces 17disposed opposite contacts 8 of integrated circuit 7 and opposite the atleast one plated-through hole 13 in each case. Analogously to FIG. 3,layer 10 carries coil 2 and coil ends 3 disposed opposite contacts 8 ofintegrated circuit 7 pointing in their direction and opposite the atleast one plated-through hole 13 in each case.

FIG. 6 shows chip card 1 shown in FIG. 2, which was produced bylaminating the layer stack shown in FIG. 5, in cross section along lineA—A. The laminating process causes coil ends 3 to be pressed against theat least one plated-through hole 13 in each case and against contacts 8of integrated circuit 7 facing them, thereby creating electroconductiveconnections. On the opposite side of layer 9 electroconductive surfaces17 are pressed against contacts 8 of integrated circuit 7 facing themand against the at least one plated-through hole 13 in each case, sothat electroconductive connections likewise arise here. Altogether,lamination causes coil ends 3 to be connected with electroconductivesurfaces 17 via the at least one plated-through hole 13, and both coilends 3 and electroconductive surfaces 17 to be electrically connectedwith contacts 8 of integrated circuit 7 facing them in each case.

In the embodiment of inventive chip card 1 shown in FIG. 6, double-sidedcontacting also, on the one hand, has the effect of low sensitivity tobending stress or other stresses which may lead to contact problems and,on the other hand, offers a universal mounting possibility forintegrated circuit 7 which can also carry contacts 8 on only one sideand can then alternatively be mounted so that contacts 8 point towardlayer 10 or toward layer 11.

The layer sequence shown in the described embodiments is to be regardedas only one of many possibilities. Thus, any other layer structures cansimilarly be used for realizing the inventive idea. The essential thingis that double-sided contacting of electronic module 4 or integratedcircuit 7 is possible or that, as an alternative thereto, electronicmodules 4 or integrated circuits 7 having contact surfaces 5 or contacts8 on only one side can alternatively be mounted in such a way thatcontact surfaces 5 or contacts 8 point alternatively to one or the othermain face of the chip card.

Coil 2 can also be applied alternatively to a single layer on one orboth sides or be distributed over a plurality of layers.

In a modification of the invention, coil 2 is applied partly to layer 10and partly to layer 11. The two coil parts are interconnected through atleast one plated-through hole in layer 9. Layers 10 and 11 each carryone coil end 3 and one electroconductive surface 17 which is connectedwith coil end 3 of other layer 11 or 10 via at least one plated-throughhole 13 in layer 9 in each case.

In a further modification of the invention, at least part of coil 2,coil ends 3 and/or electroconductive surfaces 17 is applied to layer 9having electronic module 4 or integrated circuit 7, whereby thearrangement of the individual components in the card can be retained.

What is claimed is:
 1. A contactlessly operated data carrier (1) havingat least one transfer element (2) for exchanging data contactlessly withan external device, and an electronic module (4) having contact surfaces(5) for establishing an electric connection with the transfer element(2) and containing an integrated circuit (7) which delivers or processesthe data, characterized in that the data carrier (1) haselectroconductive surfaces (3, 17) adjacent the two main faces of theelectronic module (4) and substantially opposite each other, theelectroconductive surfaces (3, 17) of the data carrier (1) areelectrically connected with the opposing contact surfaces (5) of theelectronic module (4) in each case, the electroconductive surfaces (3,17) of the data carrier (1) are electrically interconnected in pairs bymeans of plated-through holes (13), and each pair of electroconductivesurfaces (3, 17) is electrically connected with the transfer element(2).
 2. A contactlessly operated data carrier (1) having at least onetransfer element (2) for exchanging data contactlessly with an externaldevice, and an integrated circuit (7) which delivers or processes thedata and has contacts (8) for establishing an electric connection withthe at least one transfer element (2), characterized in that the datacarrier (1) has electroconductive surfaces (3, 17) opposite the two mainfaces of the integrated circuit (7) and substantially opposite eachother, the electroconductive surfaces of the data carrier (1) areelectrically connected with the opposing contacts (8) of the integratedcircuit (7) in each case, the electroconductive surfaces (3, 17) of thedata carrier (1) are electrically interconnected in pairs by means ofplated-through holes (13), and each pair of electroconductive surfaces(3, 17) is electrically connected with the transfer element (2).
 3. Adata carrier according to claim 1, characterized in that the electronicmodule (4) has contact surfaces (5) on both main faces which areinterconnected in pairs.
 4. A data carrier according to claim 1,characterized in that the contact surfaces (5) of the electronic module(4) are continuous between the two main faces of the electronic module(4).
 5. A data carrier according to claim 1, characterized in that atleast part of the electroconductive surfaces (3, 17) is part of the atleast one transfer element (2).
 6. A data carrier according to claim 1,characterized in that the transfer element (2) is a printed coil.
 7. Adata carrier according to claim 1, characterized in that theelectroconductive surfaces (3, 17) are applied by printing technology.8. A data carrier according to claim 1, characterized in that the datacarrier is a chip card.
 9. A method for producing a data carrier (1)comprising the steps of incorporating an electronic module (4) having anintegrated circuit (7) and contact surfaces (5), or an integratedcircuit (7) having contacts (8), into a first layer (9), applyingelectroconductive surfaces (17) to a second layer (11), applying atransfer element (2) and further electroconductive surfaces (3) to atleast one third layer, the electroconductive surfaces (3) being part ofthe transfer element (2) or being electrically connected with thetransfer element (2), disposing the stated layers in a stack, the firstlayer (9) with the electronic module (4) coming to lie between thesecond layer (11) and the at least one third layer (10), laminating thestack into a compound, an electric contact being established between thecontact surfaces (5) of the electronic module (4) and the particularopposing electroconductive surfaces (3, 17), and. a contact (13) isfurther established between the electroconductive surfaces (3, 17), thesecond layer (11) and the third layer (10).
 10. A method according toclaim 9, characterized in that the transfer element (2) and/or theelectroconductive surfaces (3, 17) are not applied to the second layer(11) and/or the at least one third layer (10), but to the side oppositethe particular layer (11, 10) in the stack, of the first layer (9) intowhich the electronic module (4) is incorporated.